Turbine rotor positioning issue
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Is the turbine rotor positioned using the K value or the thrust disc? There’s no wealth in the answers either; I don’t know how to do it. Let’s treat it as an opportunity to learn from each other – let’s discuss it together.
I’m not sure what you mean by ‘positioning’. Generally, we perform positioning when adjusting the instruments; that is, during installation we first ensure that the rotor’s serial number is correct, and then, when zeroing out the corresponding instruments, we fix the rotor on the low-voltage side to set the instrument’s zero point. I hope this helps you.
The positioning issue of the turbine rotor: Method 1. The positioning of a turbine is generally achieved by ensuring that the nozzle clearance meets the required values. In other words, during maintenance, first push the rotor to a range where the nozzle clearance meets the specifications, record the relevant data, and then move the rotor in the direction of the main thrust bearing pads. If there is still some clearance when moving it in that direction, and the thrust clearance is within acceptable limits, then adjustments must be made using shims to eliminate that clearance. If the rotor cannot be moved, or if the thrust bearing pads cannot be inserted even when the nozzle clearance meets the requirements, then it may be necessary to thin the shims used for adjusting the thrust bearings. Of course, in such cases, it is important to take into account the required values for the thrust clearance as well. Method 2: When the thrust clearance meets the requirements, the turbine rotor can be pushed to the main thrust position of the thrust bearings. The clearance of the first-stage nozzles is then measured; if this clearance is smaller than the designed value, the adjustment shims behind the main thrust bearing are thinned. To maintain the same thrust clearance, the adjustment shims behind the secondary thrust bearings are increased accordingly ； If the nozzle clearance is larger than the design value, then thicken the adjustment shim behind the main thrust pad, and correspondingly thin the adjustment shim behind the secondary thrust pad. Method 3: If both the thrust clearance and the nozzle clearance do not meet the technical requirements, then you need to take Method 2 into account as well in order to determine the appropriate thickness of the adjustment shims.
The K value is key to ensuring output (specified by the manufacturer); the thrust pads are adjustable
Prioritize ensuring the nozzle gap, and based on it, comprehensively consider the adjustment of the thrust gap.